Do No Harm
by Ness Frost
Summary: Sequel to Hope in the Dark. The crisis might be over, but the work is far from finished. Zuko is still recovering, and his best hope of doing that is with Katara's aid... but before she can help him, she has some demons of her own to face.
1. Aftermath

**Disclaimer:** I do not own A:tLA.

* * *

It took a few seconds, waking up, first to place the sense of profound dread, and then to realize that there was no longer any necessity for it.

At least, that was what the _rational_ part of Iroh's mind told him. That didn't change the fact that the first thing he did when he woke was throw himself from his room wearing little more than a robe and all but dash to the door that was one down from his—only to be startled at the sight of a girl in thick makeup and green dress already standing outside.

"Good morning," Suki greeted as Iroh blinked at her. She smiled. "I thought I'd do what I could, since the last set of guards didn't seem up to the task."

"Every effort you make, no matter how small, is much appreciated." Iroh gave her a deep bow before she stood aside so that he could open the door.

At the sight of the room's occupants, he could not help but smile. Four teenagers were sprawled all over the floor: Aang and Katara, hands entwined, slumped up together against the side of the bed; Sokka, meanwhile, lay with roughly half of his body sprawled over the scattered remains of what had once been someone's bedding, snoring loudly, while Toph had chosen the Water Tribesman's arm as her pillow. A spot of her drool was slowly accumulating on his sleeve. Picking his way over and through the unconscious bodies, Iroh made his way back to the chair he'd vacated the night before.

His nephew was sleeping fitfully, but he was at least sleeping. Zuko's eyes were sunken, his skin carrying an unhealthy grayish cast, but he was alive and he was breathing thanks to Katara and Aang, and Iroh was profoundly grateful for what they did have. True, there would be lingering problems, but that Zuko was even around to have problems was nothing short of a miracle. Reaching out, he brushed some of Zuko's shaggy hair out of his face before taking his second son's hand into his own.

Zuko's pulse fluttered weakly under his fingers, testimony to the strain his heart had endured two nights before, both when the poison had stopped its beat and when Katara had forced it back to life. He did not stir when Iroh took his hand, and Iroh let him sleep. Right now, they all needed it.

Even after Katara had pulled his nephew from the jaws of death, things had been touch and go. That first night, she'd been healing until moonset, and they'd all stayed awake (with the notable exception of Aang, who'd collapsed on the floor as soon as it had become apparent that Zuko's life was no longer in imminent danger—the little airbender had earned it, having already stayed awake a day and a night to help Zuko breathe). Even after Katara had stopped for a rest, however, every several hours Zuko would jolt awake in a panic, gasping desperately to take in even a lungful of air, and Iroh would prop him upright to ease his breathing, rubbing his nephew's back as he waited for Zuko to begin taking the air normally again and his own heart to stop hammering in his chest.

The first few times, he had woken Katara, who'd frowned as she ran her water over Zuko's chest and back, but eventually said that there wasn't much to be done except wait for it to pass. If it didn't, they would need to enlist Aang's help again.

Of course, Zuko's health was far from the only thing on Iroh's mind.

Now that they were no longer frantically scrambling to keep his nephew from dying, it was time to think about what came next. It was clear that Zuko would need time and care to recover, and plenty of both, but Iroh was confident in Katara's ability to provide him with the treatment he needed. It was also ill-advised for Zuko to over-stress himself with his responsibilities while his body was still healing, but if left without the authority of its Fire Lord during a period of such political instability, the nation risked falling into chaos and anarchy. As such, Iroh's duty was also clear.

Contemplating how they had gotten into this situation in the first place was far more troubling. They might have caught the would-be assassin along with one of her contemporaries, but she had not been acting alone. _Someone_ had recruited her from the Earth Kingdom colonies, channeling what might have once been a negotiable situation into murderous intent. _Someone_ had provided her with the poisoned blade along with information on the guard shifts and the layout of the palace. Most disturbingly of all, _someone_ —from what Mai had told him, far too many _someones_ —was still overwhelmingly loyal to his brother.

If they didn't get to the bottom of this conspiracy, and soon, then _someone_ was going to try again.

This ordeal was far from over.

* * *

"Okay. Here's the plan." Sokka slammed a piece of paper down on the table, upsetting their breakfasts (it was actually a lot closer to lunchtime, but on a day like today nobody was counting) and eliciting a startled protest from Toph. "We don't know who or where the Ozai loyalists are, but we do know that someone was in a position to give the assassin some critical information, and nobody's safe until we find out who. I've drawn up a list of everyone who works in the palace, starting with those who are closest to Zuko." He pushed the piece of paper across the table. "Toph, I need you to question _everybody_ on that list, from the top down—"

"Um, Snoozles—"

"I know, I know." Sokka spread his hands outward in a defensive gesture. "I was just getting to that part. That's why you're going to be working with Zuko's gloomy girlfriend." He turned toward Mai. "Um, no offense or anything."

" _Ex_ -girlfriend," was the only comment Mai offered, though without much emotional investment in the statement one way or the other. The food on her plate was barely touched, the noodles pushed to the side in favor of playing with two of her knives, the blades scraping against each other in a constant low-key grating of metal that was just loud enough to be a constant irritation, but not quite loud enough that anyone felt justified in asking her to stop.

"Um, right." Next, he turned to Aang. "I talked with Iroh earlier and he said he'd be taking on a lot of Zuko's duties within the Fire Nation for the time being, but from what I understand, the colonies are a complete mess. I think you should head over to the Earth Kingdom to calm down the colonists and meet with King Kuei, and make sure we don't end up with a full-scale revolt on our hands."

"Right." Aang nodded. "I'll talk to him, and see if I can convince him to put a hold on decolonization until we can get this sorted out."

"And what are _you_ going to be doing?" Toph questioned as they pushed out from the table.

"Me?" His fingers reached out to brush the hilt of the blade he now wore. It was no Space Sword, but he'd needed a weapon more short-ranged than a boomerang, and the specimens he'd found in Zuko's personal collection were about as well-made as they were going to come—had better be, since most of them were Master Piandao's own work. "I'm going to trade off on guard duty with Suki until the rest of the Kyoshi Warriors get here." Even as he spoke, his eyes drifted back in the direction from which they had come. Katara had not joined them for the meal, nor was it really necessary for her to be a part of this meeting. She had her own duties to attend to.

* * *

"Take a deep breath."

The skin of Zuko's back expanded beneath her ear as he followed her instructions, and Katara frowned. There it was again. While the fact that Zuko was breathing _at all_ was certainly an improvement over the way things had been two days ago, she did not like the sound of that wheezing rattle one bit.

"Now let it out—as slowly as you can."

When he did so, her frown deepened. The wheezing had not gone away.

"Are you still having trouble breathing?" she asked, concerned. Even as she pulled away she was streaming over the water from the bowl on the bedside table, bringing her liquid-coated hands to rest gently against his back.

"Only when I'm lying down for too long," he confessed as the room was filled with a blue glow. In Zuko-speak, that meant that things had barely improved at all—she knew full well, because Iroh had told her, exactly how many times Zuko had woken in the middle of the night in his struggles to draw a breath.

When she had healed all that she could, Katara streamed her water back into the bowl once more in favor of resting her palms against his back, skin to skin. Though she could not actually _bend_ any of it outside of a full moon, she had gotten much better at sensing body liquids, and the physical contact unfortunately confirmed what she had suspected all along: Zuko had fluid building up in his lungs.

"I'll see about getting you some more pillows. Propping yourself up a bit when you sleep ought to help." The last time she'd made the mistake of informing him of the details of what was causing his symptoms, Zuko had looked increasingly queasy before holding up a hand with a shake of his head, indicating that he didn't want to know any more. Now, Katara didn't tell him unless he asked—or if he was being particularly stubborn about taking his medicine.

As it was, she shifted the pillows that were already on the bed into an arrangement that would keep his torso slightly elevated before helping him back into a lying position. If nothing else, it would at least relieve some of the symptoms. Actually _fixing_ the problem would necessitate finding its source, and she barely knew where to start—Katara was only one water healer, and a half-trained one at that ( _why_ hadn't she continued her lessons with Yugoda?), she didn't have any Spirit Water, she no longer had the full Moon, and there was just _so much_ damage.

 _Focus on the most vital organs and the most life-threatening injury first._ With a sigh, Katara leaned down to press an ear to his chest this time, listening to his heartbeat.

There was an irregularity.

 _Did I hurt him_ _more_ _when I re-started his heart?_ she wondered as she listened to the third sound, the one that should not have been there, after the two normal beats. Agonizing over the question, however, was pointless, and Katara knew it. If she hadn't done what she had, that heart wouldn't be beating at all, irregularly or otherwise.

The only thing to be done now was mitigate the damage—whether hers or the poison's, or possibly even a lingering aftereffect of Azula's lightning, it didn't matter. The water came again to her hands as she placed her palms flat against Zuko's chest.

When she made contact, he flinched slightly, skin rippling under her fingers as if she'd touched a timid ostrich-horse. "This won't hurt at all," she reassured—instinct and habit, really, since she was telling Zuko nothing that he shouldn't already know.

"I know." Nevertheless, the tension remained evident in his body, the muscles standing out taught in his arms and his heartbeat quickening under her fingers. This did nothing to help her healing—Zuko was _hurt_ for Spirits' sake, would it kill him to _relax_ once in a while?—but nevertheless Katara did her best, easing some inflammation and knitting torn tissues back together, encouraging the blood to flow the way it was supposed to.

"Katara?"

"Hm?" Though she did not stop what she was doing, she did allow her gaze to flick back to Zuko's face, to see that he was watching her through half-lidded eyes.

"Why are you doing this?"

"I'm a healer. Helping people who are hurt is my job." _Idiot_ , she thought, but did not say out loud—even if she did mean it endearingly.

"No, I meant… why me? Why did you fight so hard to save _me?_ " The confusion in his face was genuine, she noticed with mounting concern, and she realized that, before joining their group, he must not have known real friendship—at least, friendship that wasn't tainted by Azula's manipulation and abuse.

"You really have to ask?" Katara's voice came out in a choked whisper, and her hand drifted downward to brush over the knotted scar tissue of an old lightning burn.

 _You saved us too._

* * *

"So, Master Katara, I was hoping that you would be so kind as to inform me of your progress."

In response, Katara blew out a breath. Iroh had been perfectly polite, of course, inviting her out to the garden and asking if she would care for a cup of tea (a blend which, he assured her, was also a powerful restorative), but she had known all along what he really wanted to ask.

"Well, he's recovering." She took another sip of her tea—Iroh hadn't been lying about its special properties; already Katara felt as if she had twice the energy that she'd had that morning. "I'm doing all that I can, but… he's going to need a lot of care, and a lot of time."

Iroh nodded; she had told him nothing that he hadn't expected. Then, however, he leaned forward, fixing her with his searching yellow eyes. "And yet you are worried."

Katara had forgotten how perceptive he was. To cover her hesitation, she took another sip of her tea while she considered how she wanted to word her answer. In the end, however, there was no sugar-coating it: trying to soften the blow now would only make it harder in the long term.

"There's something wrong with his heart."

Iroh stilled as she said it, and Katara went on; unlike Zuko, she knew, he would want to hear every detail that she could give. "It's not immediately life-threatening," she continued, "and if something does happen, we should have at least a little advance warning, but… if nothing's done about it, it will cause him lifelong problems. There's a chance he'll die young." Katara bit her lip. "Zuko's had a weak heart ever since the battle with Azula, and the strain when I—"

"Katara." Iroh's warm hands coming to rest atop hers where she had been clenching them into fists against the table made her come to a halt; she realized that she had tears standing in her eyes. "Nothing that has happened to my nephew is any fault of yours." His eyes were locked with hers, and Katara was sure that he _knew_ that not an hour had gone by in the past few days that she hadn't asked herself why she'd been standing so close to the arena that day rather than off to the side like Zuko had asked, why she'd frozen when Azula had shot comet-enhanced lightning her way, why she'd let the princess get the better of her while he'd been lying there for full _minutes_ with the lightning still racking his body, why she'd cut off her healing lessons the minute Pakku agreed to take her as his student, why she hadn't caught the poison earlier, why, why, why…

" _Nothing_ ," he whispered again, giving her hands a brief squeeze before letting go.

Unable to do anything else, she nodded.

"Is there anything to be done?" Iroh asked a few minutes later, having tactfully given her a moment to collect herself under the guise of taking another cup of tea, which she threw back in a single swallow, grimacing as the searing liquid worked its way down her throat.

"I don't know," she admitted. "But I'm going to do everything I can."

* * *

 **A/N:** Um... so, yeah. Remember that possible epilogue I was talking about? It... sort of ended up turning into a full-blown sequel. I just kept getting more and more ideas, and decided that there were some more things that needed to be done.

Very soon now I'll also be off fic sites entirely for a couple of months, so I decided to post this as something of a last hurrah before I leave.


	2. Rejection

Fact: Katara didn't _get_ Fire Nation bath houses.

First of all, the water was kept _hot_ , the room pumped full of steam. The second she'd walked in it was like being smothered with a muffling blanket that pressed down over her nose and mouth, and her hair was plastered to her face and her clothing clinging to her body within minutes. When she looked at Sokka beside her, it was evident that he was experiencing the same discomfort, though to his credit he didn't say anything. True, she'd occasionally found natural steam vents handy for doing yoga stretches, but that had been to loosen her muscles and sharpen her focus. Baths, the kind you took to get clean, were supposed to be _cool_ , a refreshing respite from the endless sticky Fire Nation heat, and anyway what was the point of bathing at all when the bath itself would make you even sweatier than you were before you got in?

Then again, Katara wouldn't be the one who was actually getting into the water.

"Okay," she declared as she brought the wheelchair to a halt, blocking the wheels to make sure it wouldn't move unexpectedly, before turning her attention back to its occupant. "You ready to get in?"

"Why are we doing this again?" Zuko was tilting his head back to look up at her, his face unusually pale and beads of sweat standing out against his forehead. Though he was finally strong enough to be moved short distances, the actual process had not been a pleasant one for him.

"Because when I'm holding the water around my hands I can only heal one small area at a time. If you're immersed, there's a much better chance I'll be able to get an overall picture of what's wrong." Still he hesitated, and Katara gave him a searching look as she crossed her arms. "Look, if you're that self-conscious, I can assure you I've seen—"

"What? _No!_ " At her statement Zuko blanched, Sokka snickered, and Katara glared; her brother was getting _so_ many snowballs to the face once they were finished here. "I… I guess I was just hoping to get an actual bath…"

"You can still take a bath after the session is finished." Katara peered at him closely. "If you don't want to do it, though…"

In response, however, Zuko only shook his head, indicating that they should get on with it. There was still something he was holding back, Katara could tell, but she decided to drop it for the time being; she already had more than enough to worry what with healing him physically without adding Zuko's personal issues into the whole mess.

Instead, she turned her back while Sokka helped Zuko out of his robe and into the water, waiting until her brother gave the word before she turned back around. When she did so, it was to see that Sokka's shirt had acquired a significant wet splotch, which she lifted out of his clothing with little more than a roll of her eyes. He nodded his thanks as she streamed the water back into the basin.

"I'll be right outside the door if you need me." Looking relieved to get out of the stifling heat, Sokka made his way to the only entrance, where she knew he would be standing guard until they were finished.

That left her alone in the room with Zuko. As she knelt beside him she could see that he was stretched out fully under the water, with his head leaning back against the side of the basin and his eyes closed, and even though the unobservant would have taken him for relaxed, Katara could see that his eyes were screwed shut and his breathing was rapid.

"This shouldn't be all that different from a normal session," she explained, letting her hands hover over the water. "Try to relax."

No sooner had she taken hold of the water, however, than Zuko jerked and curled in on himself, splashing water all over the floor and Katara alike.

"Why do you always tell me to relax right before you're about to do something excruciatingly painful?"

"The only reason it hurts is because _you_ keep tensing up," Katara shot back, though she immediately cursed herself for letting her frustration get the better of her; the last thing they needed right now was another fight between her and Zuko. Sitting back, she busied herself with lifting the water out of her clothing while she took a series of deep breaths.

"This really will go a lot more smoothly for you if you're relaxed," she continued more gently once she was sure she had herself back under control. "You can even try meditating, if it helps."

At least she knew that Zuko was proficient at meditation; she knew (because she hadn't trusted him, and thus had watched him like a scorpion-hawk throughout every waking moment of their stay at the Western Air Temple) that he'd made a habit of meditating every morning at sunrise, and that he'd made Aang do it before firebending practice as well. After a moment he nodded, letting out a breath as his eyes slipped closed.

Katara gave him a few minutes to ease into the routine, waiting until his taut muscles had relaxed and his breathing had found an even rhythm before she held her hands over the water once more. This time, she started out slowly, not even trying to heal at first but merely scanning his body, letting the water show her the damage.

Just as she'd feared, it was extensive. Several vital organs were barely functioning, or even worse were doing the wrong thing entirely, leading to a chain reaction that caused even more damage. Even though Katara had cleared out the external poison, she would have her work cut out for her making sure that Zuko's system didn't slowly poison itself.

It was the interplay of these various systems that Katara focused on now: not just what was wrong, but the various factors that were keeping it from mending on its own and the additional problems that it was causing in turn. _The body isn't just a collection of isolated organs_ , she reminded herself as she continued her scan. _It's so many different systems working_ _together_ _that makes a healthy, living human._ If she was going to heal Zuko effectively, she would have to heal _all_ of him, not just keep patching up the most vital organs again and again while they kept crashing because the rest of him wasn't working as it should.

Letting out a sigh of her own, Katara got to work. She started out slowly, giving a gentle nudge here and healing a torn tissue there, trying as she did to maintain her focus on how each part of the body was connected to every other part. It was incredibly involved work, and before long Katara was deep into a healing trance, blind and deaf to the world around her.

Perhaps that was why she didn't notice when Zuko tensed once more.

In her healing so far, she had not yet touched his heart. Being in semi-uncharted territory, Katara had wanted to start with something smaller, and less likely to do serious harm if she did make a slip. As she slowly got the hang of the technique, however, her confidence increased, and she knew that she could not let it go forever. The frown of concentration on her face intensified as she expanded her healing, reaching out to include his heart while still maintaining her awareness of the rest of his body. That uneven beat was a sign of something that was going to cause him serious problems unless Katara did something to fix it. Maybe if she just—

This time, she wasn't so much splashed as _engulfed_ in a wave of water. Gasping, Katara was jerked back to reality, the transition so sudden that it took her a few seconds to regain her bearings, remember that she was in a Fire Nation bath house, question why her face was covered with water, and realize that Zuko had lurched out of the tub again and was now using one hand to grip her arm hard enough to leave finger-shaped bruises, the other clenched in a fist over his heart.

"It's okay, it's okay, you're not hurt," and then, when he still showed no sign of letting go, " _SOKKA!_ "

Immediately her brother burst into the room, wild-eyed and with sword drawn; when he saw what was happening he sheathed the blade but looked no less wary as he came right up to the tub and took hold of Zuko's fingers, gently prying them from her arm and offering his own hand to clasp instead. "What happened?"

"I don't know." Her forearm now bore four dark, finger-shaped bruises that were already beginning to purple; wincing, she dunked it into the water until the marks faded. "Things were going so well, but then I started to heal his heart, and out of nowhere he freaked out—"

"It was not 'out of nowhere,' and I did _not_ freak out," Zuko growled. By this point he had regained enough presence of mind to release Sokka's hand, but was still pressing a fist to his heart as if trying to shield it from further abuse. He glared. "I don't know what you were trying to do, but excuse me for thinking something's wrong when it feels like you're twisting my insides into knots—"

"It only hurts because you're _making_ it hurt!" Unfortunately, her frustration was getting the better of her again, and this time Katara could no longer hold herself in. "If you would just relax and _trust me_ like I keep telling you to—"

"It's a little hard to trust you to know what's best for me if you won't even _believe_ me when I tell you something's painful!" His breath was coming in harsh gasps, and he was glaring at her through slitted yellow eyes.

 _He's not angry_ , she realized. _He's afraid, and in pain, and lashing out because he has no idea what's happening to him or why he's not getting better…_

"I _do_ believe you." Reaching out, Katara rested a hand on his shoulder. "I just think you're confused about what's causing it. I'm listening to what you're saying, Zuko. I am." She let out a sigh. "But it goes both ways. You also have to trust me to know what I'm doing."

Slowly, he settled back down into the water, letting his breath out in a long exhale. "Fine. But we're not doing any more of this. Not today."

That tone was the same one she'd heard him use when talking to a particularly stubborn manufacturer that she'd brought to his attention not two months after the war had ended; after weeks of reasoning from her and Aang had gotten them nowhere, she'd appealed to Zuko for help, and he'd called the man before him where he'd explained in no uncertain terms that the factory could either clean up its own waste, or it would find itself removed from the river. That was the last anyone had heard of the matter.

Zuko was speaking exactly the same way now, and Katara knew that his decision was final. She rubbed her forehead in frustration. As short as her lessons with Yugoda had been, there was one thing that the older woman had made very, very clear: while a healer was to _offer_ help at all times, to anyone who needed it, she was also not to force her healing on anyone who didn't want it. Unless someone's life was in immediate danger, then as much as they had the right to medical aid, they also had a right to refuse it—regardless of whether it would make their lives more painful in the long run. Zuko had given her a clear refusal, and Katara knew him well enough by this point to know that he wasn't going to change his mind. Besides, she thought, he was so tense now that she could not heal him to greatest effect anyway. Better to let the matter rest for now, regain her energy, and try again another time.

"Have a nice bath," she said, before moving to take Sokka's place outside of the door.

* * *

 **A/N:** Those familiar with _Korra_ Season 4 will recognize this scene.

One thing that drives me absolutely _up the wall_ is (almost always shipping) fics where Katara sees Zuko with his clothes off, or even with just his _shirt_ off, and immediately gets flustered by uncontrollable attraction. Seriously, Katara is a healer. Katara has _delivered babies_. Katara is _not_ going to be fazed by the sight of the human body.

Granted, I also think it's funnier to have Katara casually inform the Fire Lord that he don't got nothin' she hasn't seen before, but maybe that's just me. :)


	3. Discussion

Katara desperately wished Aang were here right now.

In times like this, her first instinct was to seek advice from people she loved and whose judgment she trusted. Except this time, she couldn't: her Gran-Gran was down in the South Pole, Aang was in Ba Sing Se, and though she loved her brother dearly Sokka just didn't understand bending; he would be no help. She wished she could have at least sent a letter, but they had already agreed not to trust any sensitive information to a piece of parchment, lest it fall into the wrong hands. Katara was on her own.

Zuko wasn't getting better.

It had been almost three weeks now, and though she had tried everything she could think of to heal him, he continued to have a bad reaction every time she touched his heart, and fear of inadvertently doing even more damage had forced her to reluctantly pull back. At this point, she was mostly easing symptoms.

It was the trauma of bloodbending, she was sure of it now. _She_ still woke in a cold sweat at least once a month from the memory of what Hama had done to her, and though her own actions had been well-meaning, she had touched Zuko in a way that was far more intimate ( _violating_ , a small part of her mind whispered), at a time when he was completely helpless and completely at her mercy. Never mind that she had forced his stilled heart back into beating and his idle lungs to draw breath, or that his conscious mind knew she would never willfully harm him: his _body_ still remembered the agonizing pain, control ripped away with a flick of the wrist. Once you had learned how easily your own body could be turned against you, she knew, you never truly felt safe again.

Letting out a sigh, Katara looked up at the waxing Moon. Only one more week, and its once-welcome pull on her bending would be tainted by the memory of another's malicious pull on her blood.

"Katara?"

Looking over her shoulder, she gave a slight smile as she saw her brother emerging onto the balcony behind her. "Looking to moongaze?" she asked.

"Guess so." He leaned against the railing next to her, and also tilted his head back to admire the celestial body. Even though he wasn't a waterbender, she knew, Sokka had his own connection to the Moon. As they slowly drifted apart in pursuing their vastly different walks of life, it was nice to have one thing she still felt she could share with him.

"So what's on your mind?" he asked abruptly, after a few minutes had passed in silence.

Katara started. Thick as he could be at times, it was easy to forget her brother's uncanny ability to always know when something was bothering her. Even when she didn't answer right away, he waited, not staring, only leaning his arms against the railing while he waited for her to be ready.

"Do you ever think about it?" she whispered at last. "Hama," she continued in answer to his puzzled expression. "The puppetmaster."

"Not if I can help it." His nose wrinkled in distaste. Then, however, horror dawned on his face as he realized what she was implying. "Oh _La_ , that's what you were—!" He didn't even bother to finish his sentence before his arms were around her and he was holding her close against his chest.

All at once, she couldn't breathe. A choked gasp tore its way from her throat, and before she knew it she was sobbing into her brother's shirt. All the while his hand was rubbing her back, and he didn't even tease her when she pulled away, even though she knew her eyes must have been rimmed with red even in the moonlight.

"How do you _deal_ with it?" she whispered, wrapping her arms around her body as she turned back to the Moon. "After she did it to you too, and she nearly made you and Aang kill each other…"

"Well, it makes sense, doesn't it?" Even after they'd pulled away Sokka had left a hand on her shoulder, and was looking at her with concern. "There are only two people in the world who know how to bloodbend, Hama's locked up, and I know you're not going to do that to anyone—well, not without really good reason," he hastily amended. "…Katara?"

Though he'd probably intended the words to be reassuring, in practice they had the exact opposite effect. All at once she had turned from him, staring down into the palace grounds, unable to look her brother in the face while she voiced her shame. "I did it to the captain of the Southern Raiders." Her voice came out in a whisper.

"You did what?" Sokka's voice was equally quiet, and thin with shock.

He would be shocked: prior to tonight, the only other person who had known of her actions was Zuko. Even with him, she'd never talked much of what had happened on that adventure—everything that needed to be said, they'd said through their actions—but they had had one brief discussion, on their way to Ember Island, concerning which details they should share with the others. They'd agreed that it would be best to tell their friends the full story of what had happened between her and Yon Rha—but _only_ about her encounter with Yon Rha. There were only so many old wounds she could reopen at once.

"I… I was angry," she continued, still not looking at Sokka, rubbing her arms as if the shame were a layer of filth that she could scrub away. "We'd managed to find the fleet, but I had no idea that Yon Rha had retired a long time ago. I just burst onto the bridge without getting a good look at the captain's face, and by the time I realized I had the wrong man, I'd already—" She had to stop there, bile welling in her throat.

"I think that what scares me most," she continued after a few minutes in which her brother didn't respond and she was afraid to prompt him, "isn't that it was done to me, but that I can do it to someone else, not to save lives but because I want to _hurt_. That I have the capacity for that kind of hate…"

"Look, Katara…" He stepped up to the railing beside her, and when she finally dared to look his face was not angry, or disgusted, only infinitely sad. "I'm not going to pretend that what you did was right. But… I also don't know what I would have done in your place two or three years ago, if I thought I'd caught the guy who murdered Mom. I do know one thing, though." His arm came up to wrap around her shoulders. "No matter what you do, you'll always be my sister. Nothing that happens is ever going to change that."

Relief washed over her like an ocean wave, and finally Katara was free to relax into her brother's arms and remember a time before the war had ripped their family apart.

* * *

"Come in."

At his call Katara pushed open the door. "You wanted to talk to me?"

Zuko was sitting up in bed, an open scroll in his hands, but he rolled it back up as she entered. "Yeah, I did." With a sigh, he set the scroll back on a rather large pile that was resting atop his bedside table. "Petitions," he explained at her curious look. "Uncle's been taking over a lot, but there are still a few things I have to sign personally."

"Doesn't look fun." Katara wrinkled her nose. As tedious and demanding as the Fire Lord's job was, however, she could tell that Zuko wanted to get back to it. He wasn't the sort of person who could enjoy staying idle for extended periods of time.

"What's going to happen if you can't heal me?"

Katara started. She had not expected the question; as a matter of fact she was used to him deliberately avoiding any details of what was wrong with his body. Now, however, Zuko was looking at her intently, and there was no doubt in her mind that this was what he had called her in here to ask.

Slowly, Katara made her way to his bedside and pulled up a chair; he reached over to move a few more scrolls off of the seat so she could sit down. "What, exactly, do you want to know?" She had to fold her hands in her lap to hide their trembling.

"Don't give me the gruesome details. Just…" He too fidgeted with his hands, clenching them briefly in the sheets. "How long am I going to live?" he blurted out at last.

Her fingers clenched around each other harder. "I can't just give you a number, you know. It isn't that simple. Even if I do nothing, there's a chance you could get really lucky and make it to well over a hundred… or I could heal you completely, and you could still walk outside and get hit by lightning tomorrow. Healers can make projections, but we aren't fortune tellers."

"So give me your best guess." In spite of the situation, he managed to smile a bit. "I doubt I'll get killed by lightning."

"That's true." Katara's hands were now fidgeting with the hem of her skirt. "In the end, a lot depends on how well you manage it… but I can almost certainly say that your life is going to be shorter than it would have otherwise."

"I've already figured that out for myself, Katara. That's not what I'm asking."

She took a deep breath. "For your twenties and thirties, you'll probably be fine. You'll most likely experience dizzy spells and shortness of breath, and you'll have to avoid exertion—that means no more firebending—but you'll probably be fine. It's when you start getting older that you'll be at real risk of dying. Once you get into your fifties and sixties—possibly even your forties—it's not a question of if your heart will give out, it's a question of when. In any case, I'm not liking your chances of meeting your grandchildren."

"I see." Zuko's grip on the sheets also tightened, and his eyes flicked away. "So what are the chances that you won't be able to heal me?"

"Don't write me off yet. I'm still doing everything I can, and I'm sure I'll find a way." She laid a hand on his shoulder. "I will." Though he gave a slight nod, he still wasn't looking at her, and she let out a sigh. "But Zuko… I can only help you as much as you'll _let_ me help you. If you want to get better, it might mean letting me do something that you really won't like."

At that, he finally stopped looking away from her, though his eyes were squeezed closed. "You're talking about bloodbending again."

"I'm sorry." Her grip on his shoulder tightened. "But consider the alternative. A few minutes of agony now, or a guaranteed early death…" Somehow, Katara had known all along that it would come to this. She'd already thought about it extensively, and this was the only solution that she'd been able to find.

Finally, he nodded, blowing out a breath—but the muscles in his shoulders were tense as rocks, the rest of his body rigid beneath the sheets. "I'll be here when you're ready."

It was a clear dismissal. With a sigh, Katara stood up and left the room.

* * *

"Are you busy right now?"

"Why, not at all! Please, come in and have a cup of tea."

He was probably exaggerating his leisure—Iroh, she knew, had been spending any and all free time with his nephew, and she could see for herself the mountain of scrolls that had amassed on the desk—but she took his invitation at face value nonetheless. This was important.

"So," he began as he poured her a steaming cup of tea, which she accepted gladly—she had yet to meet anybody who could brew tea as well as Iroh. "To what do I owe the pleasure of this visit?"

"Well, I… I might have found a way to heal Zuko's heart. For good, this time." Iroh only nodded, and Katara could tell that he knew she had more to say. "The thing is, it's going to involve something that's extremely painful and traumatizing for him, and I don't know how badly that'll affect my healing. He's already been resisting me every time I try to heal him, and I don't want to put him through this more than once, but if he doesn't trust me…"

"I see." With a sigh, Iroh set down his cup. "Katara. I take it you have come here to ask for my advice on this matter." She nodded. "Are you willing to consider an answer that you aren't going to like?"

"Yes." She spoke decisively, also setting down her cup after one last swallow of tea. "As a healer, it's my job—no, it's my _duty_ —to look after Zuko's health. I need whatever information I can get, even if it is unpleasant."

"Then, have you considered the possibility that the problem is not entirely with Zuko?"

"I'm not sure I understand." She'd meant what she'd said, and was trying very hard not to be offended, but somehow Katara thought that a point had been missed along the way. "It's not like I'm _trying_ to hurt him, but sometimes in medicine painful things are necessary. It's like… like a broken bone won't heal right, unless it's set first. Zuko knows this; I've explained it to him, and he knows why it's necessary. But I can't make bloodbending not hurt—"

"How do you know?"

Iroh, who had been listening quite calmly, chose that moment to interrupt, and his question brought Katara up short. She looked at him as if he'd asked her why waterbenders didn't live in the desert.

"I know because _I know what it's like_." Her voice, she found, was coming out in a whisper, and she wrapped her arms around herself protectively. "Another person is grabbing hold of the liquids in your body, forcing them to move in ways they don't want to go, your body is no longer your own, and it _hurts_." She rubbed her arms, hunching down tighter into her chair. "Don't ask me how, but I do know firsthand."

"I see." With a sigh, Iroh set down his teacup, sorrow welling in his eyes. "And yet, my question still stands: are you sure that the way you were introduced to it is the only one? Or are you simply allowing your own trauma to color your attempts at healing?"

"I—"

Even as she raised her voice to protest, however, Katara stopped to consider. _Did_ she know, beyond a shadow of a doubt, that excruciating pain was the only possible outcome? Hama had _intended_ to hurt her, in punishment for Katara's rejection of her lessons, just as she'd intended to hurt all those Fire Nation civilians she'd captured in retaliation for the actions of a distant military. Katara, too, had intended to hurt the man she'd thought had killed her mother, to make him feel some small portion of the pain that had been eating away at her heart since she was a little girl, and she hadn't particularly cared whether she hurt Hama—her only thought had been for her own defense, to stop her by any means possible before she did the unthinkable to Sokka and Aang. She _hadn't_ wanted to hurt Zuko—but perhaps by the time she'd reached that point, her fear of her own bending and Zuko's memory of her wrath had made that little fact cease to matter.

As she thought, Iroh watched her intently, and Katara realized that she must have been standing there with her eyes glazed over for several long moments. Snapping back out of it with a start, she looked at him, and knew what she had to do.

"Iroh? Do you think you can spare me for a bit?"

"I believe so. My nephew's life is no longer in immediate danger, after all, and we have several highly skilled physicians available if the need does arise." He took another sip of his tea. "May I ask how much time you need?"

"That depends." She let out a breath. "First, I'm going to need some information on Fire Nation prisons."

* * *

 **A/N:** This brings up some old halfway-curiosities, halfway-frustrations that I've often had with medicine in general. As far as treatment that's worse than the disease goes, I recently did a spate of spontaneous research on rabies shots and why they once had to be so awful (for the record, I never did manage to find a verifiable answer). I've also often wondered, what with all the cancer research that's been going on, why the most accepted method of treating it still involves slowly poisoning the rest of the system, and even why immunizations still have to involve jabbing a needle into a person's skin. I'm not a doctor, I'm just a humble scientist-in-training, so if anyone who does have expertise would like to explain this to me, I would _love_ to hear the answers.


	4. Breakthrough

The heat felt like a physical wave rolling over her, and Katara had to struggle not to faint. When they'd said neutralizing, as it turned out, they'd _meant_ neutralizing.

Of course, it wasn't exactly a comfortable thought that _she_ was being neutralized as well.

"Do you need to sit down?" The guard who'd escorted her in was looking at her with concern. "Most people who aren't used to it need a few minutes to acclimate."

With a grateful nod, Katara took the indicated chair, taking a few minutes to close her eyes and breathe, steadily, in through her nose and out through her mouth. The air smelled of sulfur. After a few minutes, she felt safe to push herself to her feet, though her legs still wobbled slightly underneath her.

"No water past this point." The guard held out a hand.

Katara could hardly have felt more vulnerable if they'd told her to strip. Nevertheless, she unstrapped her waterskin and handed it over, then held her arms to the side while a female guard ran quick hands over her torso and legs, checking for hidden flasks or contraband. They could not afford to take any chances.

Straightening up, the guard who'd frisked her nodded, and the others gestured her to a steel door set in the side of the mountain. As the door was cranked open in a scream of gears, however, Katara took an involuntary step back.

She was looking at a cage.

The door on her side was open, true, but Katara could see the lock for which she had no key, and the rest of it was a cramped cube of solid bars with a mesh floor, barely big enough for two people, swinging precariously over the caldera by a thin steel cable.

Her fear must have been evident on her face. "The bars are for your own protection," the guard who'd escorted her in explained, stepping up. "It would be hard to explain to people's families if someone lost balance and fell.

"If you need to hold onto something," he continued, "there are handholds here and here." He pointed out several places where the bars had been wrapped with cloth. "The bare metal can get rather hot down there, hot enough to burn, so be careful where you're putting your hands. Once you're ready to come up," he indicated a slender length of rope that hung slack from the ceiling of the cage, "pull on this. If it's an emergency—you start feeling faint, or the prisoner is doing something dangerous—pull twice, and we'll get you back up as quickly as possible, though it'll be a somewhat rougher ride. We'll bring you back up again after fifteen minutes whether we've heard from you or not. If you want to see how much time you have left, flip this," he pointed out an hourglass set into the side of the cage, "once you get to the bottom." Katara nodded to show that she'd understood.

With one last deep, shaky breath, she stepped into the cage and wrapped her fingers around the indicated handholds. The door clanged shut behind her. Then, a brief jolt, and the cage was moving, swinging out over an immense lake of boiling lava, waves of heat rising up and threatening to overwhelm her, the intensity increasing with each passing second. Katara should be sweating buckets right now, she knew, but any hint of moisture was seared away the second it reached the surface of her skin. She gripped the bars harder, leaned her forehead against her hands, and focused on breathing.

" _Do you want me to come with you?_ " Sokka had asked, eyes full of concern, when she'd told him what it was she'd intended to do. He was remembering what had happened the last time she'd run off for a confrontation; she could see it in his eyes.

Katara, however, had answered him with a shake of the head. " _No,_ " she'd said, softly but with conviction. " _Thanks for the offer, but this is something I have to do on my own._ "

The cage ground to a halt, swinging from side to side with a motion that combined with the heat to make her feel queasy and lightheaded. She had reached the bottom.

When she reached out to flip the hourglass, her hand was shaking. Her eyes, however, were not on the hourglass: Katara was looking past it, past it and into the bars of the other cage that was now directly across from her, her eyes locked on its occupant.

"Hello, Hama," she heard herself saying, as if instead of a prison they were back at the inn and about to sit down to tea.

Slowly, the other woman looked up. Curtains of white hair hung down around her head, hiding her eyes. Her mouth, though… her mouth was spread wide, in that same insane grin she'd worn when she'd tortured Katara, when she'd made puppets of Sokka and Aang to force her into learning the horrible technique against her will.

Katara hadn't expected her to be broken. Half a lifetime in a Fire Nation prison hadn't done it; a mere year in here wasn't likely to either. Still, it was unnerving that Hama could still look at her not with anger or resignation, but with the self-satisfaction of having accomplished her life's goal: she'd let another bloodbender out into the world.

"Hello, Katara." That self-satisfied smile never left her face. "I've been expecting you."

Almost without her noticing, her fingers tightened around the bars hard enough for her to feel the heat of the metal even through the cloth before she hastily forced them open and clenched her fists at her sides instead. She'd come here for closure. Instead, Hama was twisting the encounter to give herself the upper hand—just as she always had.

Katara opened her mouth—angry, humiliated—but no retort would come out. Instead, she could only glare across the bars, and once again Hama was the one to speak.

"So." Her voice was like ice in summer, cold and slick. "Whom did you use it on?"

There was no need for Katara to ask what she meant. "Fire Lord Zuko." Her voice came out in a whisper.

Hama's grin widened. "Better," she cackled. "Far better than even I would have dreamed. You surpassed even my wildest expectations, Katara."

"He'd been poisoned." She wanted her voice to be defiant, but instead it only came out weak and pleading, as if she were trying to defend herself after being caught in a terrible crime. "His body was shutting down. He'd stopped breathing. His heart had stopped beating. And I… I _made_ it beat again."

Something in her had been hoping that that information—that she'd taken Hama's intended vengeance and instead used it to save a life—would wipe the glee off the other woman's face, would make her angry or disappointed or would cause her to crumple in defeat. Instead, she let out yet another cackle.

"What's so funny?" Katara demanded.

"It's perfect." Hama's grin was now so wide Katara was surprised it hadn't physically split her face.

"How is that perfect?" She was beginning to panic, her heart pounding against her ribcage and bile welling in her throat. Her head spun. "Did you even hear what I said, Hama? I used _your_ technique _to save his life_."

"You never seriously believed I actually wanted you to kill anyone, did you?"

This time, no retort would come. She was swaying on her feet, and had to grip the bars just to keep herself upright.

"Death would have been a welcome release, after what the Fire Nation put our tribe through." _Now_ she was angry, her voice coming out in a hiss and her eyes narrowed to slits. "They should have killed us when they caught us. It would have been more merciful than being starved, chained, dehydrated and brutally beaten day after day for _years_ on end, with no hope of release. Do you think that _death_ would be sufficient to repay such a crime?" No: she already knew the answer. They'd found it, when they'd found all those people screaming under the mountain…

"The people of the Fire Nation do not need to die. They need to _suffer_ , as our people have suffered at their hands. And you—you have continued my work, whether you wanted to or not! Tell me, Katara." She was getting up now, moving to stand at the near end of her cage, and though they were too far apart to touch even if they were to both lean against the bars and reach out their hands, it was still too close. "Did he thank you, when you were finished? Or was he too preoccupied with writhing in agony? No, he is going to remember that moment, remember your _power_ over him, for the rest of his life—and thanks to you, it is going to be a very long life indeed."

 _A hand clenched around her forearm, hard enough to leave bruises…_

 _Tears spilling from beneath his good eyelid as she worked her hand… Zuko_ _never_ _cried, especially not for pain…_

 _A single cracked syllable, forced in a whisper from between parched lips…_

"…he _did_ thank me."

He'd barely been able to talk—he'd barely been able to _breathe_. He'd been grasping Iroh's hand as if clinging to a lifeline. Even so, he'd undertaken the immense effort to force out the word, because as painful as it had been he _knew_ what it was she'd done for him, that she wouldn't have hurt him if she'd had any other choice.

…another choice…

"Hama," she continued, cutting the other woman off as she opened her mouth once more. "I'm truly sorry for what's been done to you, and to the rest of our people." There was plenty of sand still left in the hourglass, but Katara knew now that she would not need it—she had finally found the words she had needed to say. "But there's no longer anything I can do to help you. Help is something you have to want, and you've already chosen your path." Steadying her feet beneath her, she unclenched one of her hands from the bars, and reached upward. "Goodbye."

When her fingers closed around the rope, she only tugged once. Even though the heat was quickly overwhelming her and darkness was starting to gather at the edges of her vision, she did not want Hama to think she was running. There was simply nothing more she had to say.

Furious screams echoed from behind her as Katara closed her eyes and sagged against the bars, but she paid them no mind. Nothing Hama could say to her could hurt her anymore.

Hama had taught her bloodbending with the intention that she inflict pain, and in that, at least, she had succeeded. It had been necessary—Katara knew that. She'd known all along that sometimes, in order to help people heal, it was necessary to hurt them first: setting a broken bone, stitching a wound, cauterization to stop uncontrollable bleeding… Though she had never flinched away from doing what she had to, neither did she revel in it. She did not like to see people hurt.

Sometimes, though, there was a better way. Since she had learned water healing, Katara had not had to stitch a single suture, and it had made things better for everyone involved. Surely—surely—she could figure out a way to get past this too. Now, the only thing left was to hope that the idea taking seed in her mind actually worked.

There was no longer anything more that Katara could do for Hama—but she _could_ still help Zuko.

* * *

"Are you comfortable?"

"Does it matter?"

"I think that it does." He looked at her incredulously, and she let out a slight sigh. "Humor me."

"More or less, I guess." His shoulders moved upward in the slightest of shrugs. "Getting tired of this bed, to be honest."

"Well, hopefully you won't have to be in it for much longer." The curtains were open, allowing the white light of the full Moon to spill into the room. "So what do you say?" She tried to smile, but her mouth couldn't quite seem to find the right shape. "A few minutes of bloodbending in exchange for a long, full life?"

"Katara, it feels like you're trying to rip my heart out." His voice came out in a whisper.

"I'm not. I know that it feels that way, but I'm not, and I won't." Closing her eyes, she took a moment to gather all feelings of passive-aggressive bitterness, and then to let them go. "You do trust me when I say that, right? Please," she continued when Zuko opened his mouth. "I need your honest answer. This _is_ important."

To her surprise, he gave a slight chuckle, but when his free hand moved to rest over a star-shaped mark on his midsection, Katara understood. "I think you already know the answer to that."

"Good." A smile—a real one this time—tugged at the corners of her mouth. "Are you ready?"

"No." Though his pulse jolted under her fingers when she asked the question, his voice remained admirably steady. "But I'm never going to be ready, so just go ahead and do it."

"Do you want anyone in here with you? Sokka? Your uncle?" In answer, he only squeezed his eyes closed and shook his head, so Katara set his arm gently back down at his side and stood.

She'd already folded the covers down to his waist and draped his robe over the back of a nearby chair so she could listen to his heart, and now he lay bare-chested before her, his scars standing out lividly against his pale skin. Of course, she'd seen Zuko without his shirt on before this, on many different occasions—but this was the first time Katara had seen him look so _naked_.

"I'm going to try something a little bit different this time, and I'm going to try to make it not hurt as much. And I know this is going to sound really stupid," she said. "But try to relax."

"Relax. Right." With a visible effort he unclenched his fingers from the sheets and let his hands rest limply at his sides, taking in a few deep breaths with his eyes closed. Tension still ran through his body, but Katara had to acknowledge that he was genuinely trying, which was better than they'd been doing a week ago. Reaching out, she rested a hand against his chest, her fingertips brushing his skin with a feather-light touch.

She could feel his heartbeat.

The damage was still there, outlined clearly in Zuko's blood. This time, however, Katara knew that she could fix it. All she needed was to have faith in herself—and in him.

" _A good healer works with the body, if at all possible—not against it._ " That had been Yugoda's first lesson to her, when she'd attended that class she hadn't wanted to go to because Pakku hadn't thought she was good enough to bend with the boys. At the time, anything she might have learned had been overshadowed with resentment, the deep bitterness that she was only allowed to do something "lesser" for no better reason than the way she was born. Though her conviction to learn how to fight had not changed since that time, her views on healing had, and now Katara recalled that lesson as she counted the beats of Zuko's heart.

A contraction—she pushed. The muscle relaxed—she pulled. Bit by bit, Katara nudged the damaged tissues back into alignment, trying to work _with_ the rhythm of his heart, the flow of his blood. Everything was clear to her. It was almost as if she held Zuko's beating heart in the palm of her hand.

"Hey, Katara?" At least he spoke quietly; working with the body or not, she was still all too aware of the power she held, and did not like to think what she was capable of doing by accident if startled into an involuntary twitch. "Are you planning to start any time soon? I've had about as much suspense as I can stand."

"Actually, I already started."

"Huh? But I don't feel anything…" With a slight shift, he reached up as if to touch his chest, but Katara grabbed his hand with her free one and gently pushed it away.

"Don't," she warned him. "I'm still working. I did tell you I'd be trying something a bit different."

"A _bit_ different? But…"

"I didn't know how well this would work, and I didn't want to get your hopes up if it didn't. Now hush. I need to concentrate."

With a nod, he lay back, and this time the tension truly eased from his muscles as he let out a breath and relaxed at last. Once she saw that he truly trusted her, Katara began to work in earnest, beginning the major repairs that would keep Zuko's heart healthy and strong, hopefully well into his old age.

He was going to get past this—and, just as importantly, she was as well.

* * *

 **A/N:** A little inside joke of mine is that I like to write Zuko and Katara in every possible type of relationship imaginable— _except_ for romance. This was the story where I explored the doctor-patient aspect of their relationship. The title of the story was specifically taken from the Hippocratic Oath. Specifically, "Practice two things in your dealings with disease: either help or do not harm the patient." That sort of dynamic was what I was trying to get across here.

For the record, yes, I think that it's in character for Katara to regret not having put more effort into learning how to heal. I do _not_ think that it's in character for her to regret having learned how to fight—think about the lives she's saved specifically thanks to her skills in combat, and that argument gets thrown on its head.


End file.
